An organic EL (electroluminescent) element is a self-light-emission type electroluminescent element having a structure that an organic light-emitting medium layer is held between two electrode layers at least one of which has translucency and causes the organic light-emitting medium layer to emit light by applying a voltage between the electrodes. This organic EL element has advantages such as a wide viewing angle, a fast response speed and low power consumption, and therefore it is expected as a flat panel display used instead of a cathode-ray tube and a liquid crystal display.
But, the light-emitting medium layer of the organic EL element is composed of an organic material, and it is apt to be degraded by an influence of moisture, oxygen or heat in the atmosphere. Since this degradation lowers the light emitting performance of the organic EL element, display characteristics tend to be degraded. To prevent the organic EL element from deteriorating, there is adopted a structure that the top surface of the organic EL element formed on a glass substrate is covered by a glass substrate (glass cover) to form a hollow inner structure, and an adsorbing desiccant for moisture and the like is disposed within the hollow portion. And, there is also proposed a structure that the entire organic EL element is sealed with epoxy resin having low moisture permeability which is filled into the hollow portion between two glass substrates (see, for example, JP-A 2006-28386 (KOKAI)).
But, the structure that the adsorbing desiccant is disposed in the hollow portion cannot suppress sufficiently the organic EL element from degrading because the water-absorbing capacity of the desiccant is insufficient. The method of sealing with the epoxy resin filled into the hollow portion has problems that the organic EL element has a possibility of deterioration because the moisture contained in the epoxy resin is not controlled sufficiently and the organic EL element is deteriorated by heat applied at the time of curing because the epoxy resin has a high curing temperature.
The present invention has been achieved to solve the above-described problems, and the invention provides an organic electroluminescent element sealing composition capable of preventing deterioration of an organic electroluminescent element and an organic light-emitting device having a good light-emitting property for a long period.